1. Field of the Invention
The invention relates to a limit stop with an elastomer spring, for damping forces generated when a door or lid strike a stationary chassis part of a motor vehicle.
2. Description of the Related Art
To prevent clatter or damage to metal chassis parts or to the paint of motor vehicles, the area around the doors and lids, in particular the front hood and the trunk lid, typically includes means for damping the impact. In most situations, the impact from doors or lids closing on the respective chassis openings is dampened by a number of limit stops which are made of an elastomer material and arranged along the circumference of the opening. Suitable limit stops, frequently in the shape of the head of a mushroom, are used predominantly around the engine hood and the trunk lid, which close by their own weight through engagement with a snap-in lock. The limit stops operate as end stops for the respective closing height of the lid and absorb the acceleration forces generated by the closing lid.
The installation height for limit stops of this type should be selected so that the corresponding door or lid, when closed, is biased against that chassis so as to prevent rattle and leave only a very small gap spacing. A limit stop of this type is described, for example, in DE 199 29 953 A1. However, this document does not address the mechanical construction of the limit stop, but attempts to prevent accumulation of paint on limit stops which are already installed on the chassis when the vehicle is painted. In addition, DE 100 35 201 A1 describes a limit stop with a height which is adjustable in relation to the chassis frame. With the disclosed solution, manufacturing tolerances in the gap spacing of the lids or doors can be compensated. However, with the aforementioned conventional solutions, the spring characteristic of the buffers disadvantageously remains constant when the engine hood is closed, independent of the closing speed of the hood, so that the spring action is independent of the respective closing height of the hood. It would therefore be desirable to reduce peak forces exerted on the chassis parts, when the lid is accidentally and inadvertently dropped from a considerable height, by increasing the spring characteristic when the impact speed increases, and to also limit the depth with which the lid or door depresses the limit stop in view of the small gap spacing.
It is therefore an object of the invention to provide a limit stop with a spring characteristic which adapts within predefined limits to an increasing closing speed of a closing door or lid, and which also effectively dampens large impact forces. The limit stop should also make it possible to realize very small gap spacings.